Psychology 201: Infancy Development (Chapters 3 & 4)

Chapter 3 Physical Growth and Development Patterns

Timeline of Physical Capability: - First 12 Months: Infants become capable of sitting, standing, stooping, climbing, and usually walking. - Second Year: Rapid increases in activities such as running and climbing take place.
Growth Patterns: -
Cephalocaudal Pattern: The sequence in which the earliest growth always occurs at the top of the head. During prenatal development and early infancy, the head occupies a large portion of the total body. As individuals develop into adulthood, the head becomes smaller in relation to the rest of the body. -
Proximodistal Pattern: A sequence in which growth starts at the center of the body and moves toward the extremities. - Example: Infants control the muscles of their trunk and arms before they control their hands. They use their whole hand before they can use their fingers. - Growth Nature: Physical growth is not always smooth and continuous; it is episodic, occurring in spurts.
Height and Weight Statistics: - Average North American Newborn: $20\,\text{inches}$ long and weighs $7.5\,lbs$ . - Early Weight Loss: In the first several days of life, most newborns lose $5\%$ \text{ to } $7\%$ of their body weight before adjusting to feeding. - Weight Gain Milestones: Once adjusted, they double their birth weight by the age of $4\,\text{months}$ and triple it by their first birthday ( $12\,\text{months}$ ). - Two-Year Statistics: By age $2$ , the average child is between $32$ and $35\,\text{inches}$ , which is nearly half of their eventual adult height.

The Brain and Neural Development

Brain Composition at Birth: Contains tens of billions of nerve cells, or neurons.
Brain Protection: Because the infant\'s brain develops rapidly, protection from falls and injury is critical.
Shaken Baby Syndrome: - Involves brain swelling and hemorrhaging. - Affects hundreds of babies in the US annually. - Identified Perpetrators (National Center on Shaken Baby Syndrome, 2012): Fathers were most often the perpetrators, followed by child care providers and boyfriends of the victim’s mother.
Brain Structure: - Forebrain: Includes the cerebral cortex and structures beneath it. - Cerebral Cortex: Covers the forebrain like a wrinkled cap, consisting of two halves and four main lobes: - Frontal lobe - Occipital lobe - Temporal lobe - Parietal lobe - Lateralization: The specialization of function in one hemisphere or the other.
Neuron Anatomy: - Neuron: A nerve cell that handles information processing. - Myelin Sheath: A layer of fat cells that encases many axons. It provides insulation and helps electrical signals travel faster down the axon. - Terminal Buttons: Located at the end of the axon, these release chemicals called neurotransmitters into synapses.
Early Experience and Development: - Environmental experiences guide brain development after birth; the brain is "waiting" for experiences (sights, sounds, smells, touches, language, eye contact) to determine neural connections. - Case Study: Children in unresponsive and unstimulating Romanian orphanages showed considerably depressed brain activity compared to children in "normal" environments.
Neuro-constructivist View: - Biological processes (genes) and environmental experiences (enriched or impoverished) influence brain development. - The brain has plasticity and is context-dependent. - Brain development is closely linked with cognitive development, emphasizing interactions between experience and gene expression.

Sleep and SIDS

Sleep Duration (WHO Recommendations): - Typical Newborns: Sleep $16\text{ to }17\,\text{hours}$ a day (with variation). - 0-3 Months: $14-17\,\text{hours}$ of good-quality sleep. - 4-12 Months: $12-16\,\text{hours}$ of good-quality sleep. - 1-2 Years: $11-14\,\text{hours}$ of good-quality sleep.
REM (Rapid Eye Movement) Sleep: - Infants spend a greater amount of time in REM sleep than at any other point in their lives. - Adults spend approximately $\frac{1}{5}$ of their night in REM sleep. - REM sleep promotes brain development in infancy.
SIDS (Sudden Infant Death Syndrome): - A condition where an infant stops breathing, usually during the night, and dies suddenly without an apparent cause. - It is a leading cause of infant death in the US. - Highest Risk: At $2\text{ to }4\,\text{months}$ of age. - Risk Reduction: Risk decreases when infants sleep on their backs rather than stomachs or sides. Back sleeping increases access to fresh air and reduces overheating.

Motor Development and Reflexes

Dynamic Systems Theory: Infants assemble motor skills for perceiving and acting. Perception and action are coupled. To develop skills, infants must perceive environmental motivation and use perception to fine-tune movements to achieve goals.
Reflexes: Built-in reactions to stimuli that govern newborn movements. They are genetically carried survival mechanisms, automatic and involuntary, allowing adaptive responses before learning occurs.
Table of Newborn Reflexes: - Blinking: Stimulated by a flash of light or puff of air. Response: Closes both eyes. Pattern: Permanent. - Babinski: Sole of foot stroked. Response: Fans out toes, twists foot in. Pattern: Disappears after $9\,\text{months}$ to $1\,\text{year}$ . - Grasping: Palms touched. Response: Grasps tightly. Pattern: Weakens after $3\,\text{months}$ , disappears after $1\,\text{year}$ . - Moro (Startle): Sudden stimulation (loud noise/dropping). Response: Arches back, throws head back, flings out arms/legs, then closes them to center. Pattern: Disappears after $3\text{ to }4\,\text{months}$ . - Rooting: Cheek stroked. Response: Turns head, opens mouth, begins sucking. Pattern: Disappears after $3\text{ to }4\,\text{months}$ . - Stepping: Feet lowered to touch a surface. Response: Moves feet as if to walk. Pattern: Disappears after $3\text{ to }4\,\text{months}$ . - Sucking: Object touching mouth. Response: Sucks automatically. Pattern: Disappears after $3\text{ to }4\,\text{months}$ . - Swimming: Put face down in water. Response: Coordinated swimming movements. Pattern: Disappears after $6\text{ to }7\,\text{months}$ . - Tonic Neck: Placed on back. Response: Forms fists, turns head to the right ("fencer's pose"). Pattern: Disappears after $2\,\text{months}$ .
Gross Motor Skills Progressions: - Prone, lift head: $0-1\,\text{month}$ . - Prone, chest up, use arms for support: $2-4\,\text{months}$ . - Roll over: $2-4.5\,\text{months}$ . - Support some weight with legs: $3-6\,\text{months}$ . - Sit without support: $4.5-7.5\,\text{months}$ . - Stand with support: $5-10\,\text{months}$ . - Pull self to stand: $6-10\,\text{months}$ . - Walk using furniture for support: $7-12.5\,\text{months}$ . - Stand alone easily: $9.5-14\,\text{months}$ . - Walk alone easily: $11-14.5\,\text{months}$ .
Fine Motor Skills: Involve finely tuned movements like grasping toys, using spoons, or buttoning shirts. Developing the pincer grip often occurs around the same time as crawling.

Cognitive Development: Piaget and Vygotsky

Piaget\'s Theory: - Schemes: Infants create behavioral schemes (physical activities like sucking, looking, grasping). Toddlers/older children create mental schemes (strategies and plans). - Sensorimotor Stage: Birth to age $2$ . Infants construct understanding by coordinating sensory experiences (seeing/hearing) with motor actions (e.g., shaking a rattle). - Object Permanence: The understanding that objects continue to exist even when they cannot be seen, heard, or touched (e.g., Peek-a-boo).
Comparison: Piaget vs. Vygotsky: - Vygotsky (Sociocultural): Learning is social; children work with others. Development is driven by input from others and More Knowledgeable Others (MKOs). Context-dependent; development is continuous. Learning precedes development. Language drives thought. Social speech becomes inner speech. - Piaget (Cognitive): Learning is solitary; children learn through exploration. Development is driven by movement to the next stage. Universal stages; development is discontinuous. Development precedes learning. Thought drives language. Egocentric speech dies out and becomes social speech.

Language Development

Definition: Form of communication (spoken, written, signed) based on symbols and rules for combining them.
Developmental Steps: - Crying: Signals distress or needs. - Cooing: $2\text{ to }4\,\text{months}$ ; expresses pleasure. - Babbling: Middle of first year (e.g., "ba-ba-ba-ba"); facilitates social interaction. - Gestures: $8\text{ to }12\,\text{months}$ ; includes pointing and waving bye-bye.
Environmental Influences: - Early speech input and poverty impact skills. - Child-directed Speech: Language in a higher pitch, slower tempo, and exaggerated intonation. It captures attention and maintains social interaction.

Chapter 4: Socioemotional Development in Infancy

Socioemotional Indicators: - Early Emotional Signs: Crying, muscle tension, smiling, cooing, wiggling. - Early Social Signs: Responding to voices, enjoying being picked up, responding to cuddling, smiling at faces, crying when a person leaves.
Emotional Development: - Definition: Feelings or affect occurring during important interactions, especially regarding well-being. - Roles of Emotion: - Communication (joy, sadness, fear). - Behavioral organization (influencing social responses). - Brain Regions: Hippocampus, brain stem, and amygdala play roles in distress, excitement, and rage. - Caregiver Influence: Sensitive caregiving helps biological recovery from stressors. Maltreatment/neglect or caregiver depression negatively influences emotional development.
Types of Emotions: - Primary (First 6 months): Surprise, interest, joy, anger, sadness, fear, disgust. - Self-Conscious/Other-Conscious (Second half of 1st year to 2nd year): Jealousy, empathy, embarrassment, pride, shame, guilt. - Display Rules: Cultural rules for expressing emotions. East Asian infants often display less intense emotions than non-Latino white infants due to cultural encouragement of emotional reserve.

Crying, Smiling, and Fear

Crying Mechanisms: - Basic Cry: Rhythmic pattern: cry, silence, higher-pitched whistle. Often associated with hunger. - Anger Cry: Variation of basic cry with more excess air forced through vocal cords. - Pain Cry: Sudden long, initial loud cry followed by breath-holding; no moaning. - Note: Excessive crying at $3\,\text{months}$ is linked to double the risk of behavioral/mood problems at age $5-6$ .
Smiling: - Reflexive Smile: No response to external stimuli; occurs in the first month, usually during sleep. - Social Smile: Occurs in response to external stimuli (faces); starts as early as $2\,\text{months}$ .
Fear and Anxiety: - General Fear: First appears at $6\,\text{months}$ , peaks at $10\,\text{months}$ . - Stranger Anxiety: Fear of strangers. Appears at $6\,\text{months}$ , escalates until $1\,\text{year}$ . Less prevalent in familiar settings or with friendly strangers. - Separation Protest: Crying when caregiver leaves; peaks at $15\,\text{months}$ . - Social Referencing: Reading emotional cues in others to determine how to act. Established by the end of the first year.

Temperament and Character

Definitions: Individual differences in behavioral styles, emotions, and characteristic ways of responding (reactivity and self-regulation).
Chess and Thomas’ Classifications: - Easy Child: Positive mood, regular routines, adapts easily. - Difficult Child: Reacts negatively, cries frequently, irregular routines, slow to accept change. - Slow-to-Warm-Up Child: Low activity level, somewhat negative, low-intensity mood.
Kagan’s Behavioral Inhibition: Focuses on shy/subdued vs. sociable/extraverted children. Inhibition to the unfamiliar at age $2-3$ is linked to social phobia at age $7$ and social anxiety in adulthood.
Influences: - Biology: Moderate influence from heredity (twin studies). - Gender/Culture: Parents react differently based on gender. Behavioral inhibition is valued more in China than North America. - Goodness of Fit: Match between a child\'s temperament and environmental demands.

Personality, Self, and Independence

Erikson’s Stages: - Trust vs. Mistrust (Year 1): Trust develops through consistent, nurturing care (feeding, diapering). Mistrust arises if care is inconsistent. - Autonomy vs. Shame and Doubt (Year 2): Independence grows with motor skills (walking, climbing). Shame occurs if caregivers are impatient or overprotective.
Sense of Self: - 3 Months: Rudimentary self-recognition (mirror technique). - 2nd Year: More complete self-recognition of physical features. - Late 2nd/Early 3rd Year: Toddlers use language like "Me strong" or "My toy."

Social Orientation and Attachment

Attachment: A close emotional bond between two people. - Theories: Freud (oral satisfaction/feeding); Erikson (physical comfort/trust).
Strange Situation (Ainsworth): Observational measure involving introductions, separations, and reunions. - Securely Attached: Distressed when parent leaves, easily comforted upon return. - Insecure Avoidant: Not distressed when parent leaves, ignores parent on return (covert anxiety management). - Insecure Resistant (Anxious-Resistant): Distressed when parent leaves, seeks to punish parent/displays overt anger on return. - Insecure Disorganized: No predictable pattern; may show depression or disturbing behavior.
Social Contexts: - Reciprocal Socialization: Socialization is bi-directional. - Scaffolding: Timing interactions (like Peek-a-boo) so children learn turn-taking. - Caregiving Roles: Mothers spend more time on average; maternal interactions center on care (feeding/diapers), while paternal interactions often center on play (bouncing/tickling).", "title": "Psychology 201: Physical, Cognitive, and Socioemotional Development in Infancy"}